Technical Abstract:
A 0.4 ha planting of blueberry was established in October 2006 to evaluate the effects of cultivar (Duke and Liberty), bed type (flat versus raised beds), weed management (sawdust mulch and hand-weed control; sawdust+compost mulch with acetic acid, flaming, and hand control used as needed; and weed mat), and type and rate of fertilizer (feathermeal and liquid fish emulsion at 29 and 57 kg/ha of N) on plant growth, yield, fruit quality, irrigation requirements, and weed presence. The site was certified organic in 2008. Plants grown on raised beds were larger than those on flat ground but required more irrigation, particularly with weed mat. Weed mat resulted in the fewest weeds while sawdust+compost resulted in the most weeds. In 2008, yield was highest when 29 kg/ha of fish N was applied and when plants were grown on raised beds with weed mat. In year 3, yield averaged 1.7 kg/plant and was highest when 29 kg/ha of fish N or 57 kg/ha of feathermeal N was applied and when plants were mulched on raised beds with weed mat or sawdust+compost. Fruit were also firmer at harvest when plants were fertilized with fish rather than feathermeal and when soil was mulched with sawdust compared to weed mat. Weed mat is the least expensive option for weed control so far. Research is also underway to develop custom compost for blueberry. Composts prepared from locally available by-products averaged 42% organic matter and required addition of 2 kg of S per cubic meter of compost for acidification to pH 5.